Solef® PVDF

Solef® PVDF is perhaps the best known fluoropolymer used in the Oil & Gas industry because of its extensive use in flexible risers and flowlines since the 1990’s.

Typical properties

  • Continuous service temperature up to 130–150°C
  • Excellent chemical resistance
  • Good mechanical properties
  • Low permeability to most gases and liquids
  • High abrasion resistance
  • Excellent resistance to Rapid Gas Decompression (RGD)

 

Solef® PVDF for Flexible Risers and Flowlines

Solef® PVDF is perfectly suited to the demanding applications of deepwater subsea oil service. The complex pipe structures are designed to withstand the high pressures, temperatures and aggressive oil fluids, and Solef® PVDF is increasingly used as a barrier, thanks to its excellent long-term performance in exposure to these conditions.

Solef® PVDF is qualified to API17J up to a continuous service temperature of 130°C for 20 years, and already has a strong proven track record in these applications. Increasingly an issue is the presence of supercritical CO2 in oilfield fluids when it is used as a solvent in Enhanced Oil Recovery (EOR). Solef® PVDF was exposed to supercritical CO2 at 130°C and 150 bar to prove the chemical stability. Results showed low weight increase and low influence on mechanical properties. Fluoropolymers not only offer good chemical compatibility with supercritical CO2 at high temperature and in polluted mixtures, but can also protect the surrounding metallic structures.

Many hydrocarbon producing regions of the world are significantly sour. H2S in the presence of moisture is a serious problem for many metallic components, causing Sulphide Stress Corrosion Cracking (SSCC), Hydrogen Embrittlement (HE), Hydrogen Induced Cracking (HIC), or stress oriented HIC. Unbonded flexible pipes are an example of a product where negligible permeation of H2S through the inner pressure sheath is highly desirable. Solef® PVDF has been submitted to an exposure program at several elevated temperatures and H2S concentrations; test results confirm PVDF is only slightly affected in sour environments.

H2S permeability

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Temperature rating

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Swelling in sour environment

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Elastic modulus in sour environment

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Solef® PVDF for Umbilicals

Umbilical hoses are required to resist methanol and ethanol and have a very low permeability to such injection fluids. Solef® PVDF has been selected by high pressure hose manufacturer SPIR STAR® for these reasons, for use up to 150°C and 1,125 bar.

Elastic modulus with temperature

Solvay-oil-gas-polymers-elastic-modulus-with-temperature

 

Solef® for Pipe Liners

Fluids transported in flowlines are characterized by the presence of CO2, H2S and free water: these chemicals combined with the different flow parameters can generate a high corrosion rate of the pipelines. While corrosion can be controlled and mitigated by chemical additive injection, a small change of the chemical composition or of any flow parameters of the oil can drastically increase the corrosion rate. Polymer-lined carbon steel piping is an effective and economic alternative to the use of Corrosion Resisistant Alloys (CRA), and can reduce the use of chemical injection and maintenance costs. Solef® PVDF is a material of choice for preventing corrosion and providing long-term reliability to hydrocarbon lines.

Solef® PVDF for Coatings: Internal and External Protection of Pipelines

Solvay Specialty Polymers have developed a new Solef® PVDF material designed for direct adhesion onto metals and allowing the construction of multilayer coating systems.

This new Solef® PVDF is available as a powder coating system and provides excellent adhesion and chemical compatibility with other Solef® PVDF grades, suitable for extrusion, providing thermal insulation and mechanical strength to the steel pipe. This two-layer system may be used for the external coating of pipelines.

The traditional Electrostatic Powder Coating (EPC) system based on PVDF resins, one layer of primer and several layers of top coat, can be used for internal coatings of pipelines.

Properties of Solef® PVDF coatings:

  • Thermal stability from –30°C to 150°C
  • Thermal conductivity lower than 0.2 W/m·K
  • Water absorption < 0.02%
  • Low permeation to water over a wide range of temperature
  • Excellent mechanical and impact strength
  • Intrinsic weathering resistance
  • Excellent electrical insulation
  • Density: 1.78 g/cm